1. Field of Invention
The present invention is in the field of medical valves and in particular it is concerned with a valve suitable for drawing blood samples from an individual or for injecting to an individual through an infusion tubing system.
2. Description of Related Art
A variety of infusion tubing systems are known for various treatments requiring liquid administration to a patient. However, at times it is required to draw a blood sample through the same infusion line or to inject through the same line some treatment liquid. Such procedures are heretofore carried out by using different three-way stop cock valves and other shut-off valves.
Typically, it is a requirement to drawxe2x80x9cfreshxe2x80x9d blood samples, i.e. blood which has not been mixed with other agents, or which has not been standing for a while in a tubing section which may thus result in obtaining false indications.
It is another growing requirement that blood sampling and injecting devices, in particular those components which are exposed to the environment, be easily approachable for wiping with a disinfectant swab. Such an operation is often referred to in the art as xe2x80x9cswabbingxe2x80x9d, and, respectively swab approachable zones are referred to as xe2x80x9cswabbablexe2x80x9d.
U.S. Pat. No. 4,819,684 discloses an injection shut-off valve comprising a housing with connections for inlet end outlet lines. The housing includes an orifice for introducing an.injection syringe and a valve installed within the housing including a deformable diaphragm. In a non-injection state, the valve device seals off fluid flow between the inlet lines and the outlet lines on the one hand, and the orifice on the other hand. However, during injection, the diaphragm is deformed to create an opening such that fluid flow from the inlet to the housing is shut off. During the formation of the diaphragm the orifice is brought into fluid connection with the outlet line from the housing, thus making it possible for injecting fluid to pass through the housing into the outlet line and to the patient.
However, by some of the embodiments of the ""684 patent portions of the valve which come into contact with the syringe are not swabable, whereas in other embodiments the device is suitable only for injecting liquid therethrough, while drawing a blood sample is not possible, as the device operates as a one-way valve.
It is an object of the present invention to provide a novel sampling/injecting valve in which the above referred to disadvantages are significantly reduced or overcome, and wherein the above desiderata are fulfilled.
It is an object of the present invention to provide a novel sampling/injecting valve suitable for operating with an infusion line whereby activating of the valve is carried out by a luer-type connecting member, typically of a syringe, whereby a blood sample may be drawn from a patient or a liquid may be injected to the patient.
In accordance with the present invention, there is provided a blood sampling/injecting valve comprising:
a housing formed with a cavity extending along a longitudinal axis of the housing, said cavity having an opening adapted for sealingly receiving a syringe Luer connector; said housing further comprising an inlet port and an outlet port;
a plunger formed with a communication conduit and a flow path formed at a top face of the plunger facing the opening of the housing; said plunger being axially displaceable by the Luer connector between a flow position in which the conduit communicates between the inlet and the outlet port and a sampling/injecting position in which the flow path is in flow communication with the outlet port, while the outlet port is disconnected from the inlet port; said plunger being normally biased into said flow position. By one example, the communication conduit is an annular, peripheral groove formed at the plunger.
By one embodiment, the communication conduit is a bore transversely extending through the plunger, in which case the plunger is rotatably restrained within the cavity.
In accordance with a most preferred embodiment of the present invention, the entire space of the flow path is swabable, i.e. a disinfectant swab may be easily introduced into the flow path for disinfecting thereof.
In accordance with one design of the invention, the inlet port and the outlet port transversely extend with respect to said longitudinal axis. In accordance with one arrangement, the outlet port and the inlet port may be co-axial with one another.
By one specific embodiment, the plunger is retained within the housing by a snap-type arrangement, wherein the plunger is introduced into the cavity of the housing via the opening, overcoming a radially projecting retainer portion, typically annular.
In accordance with another specific design, the plunger is biased into the flow position by a springy portion integrally extending from a bottom face thereof bearing a bottom wall of the housing.
In order to obtain improved sealing in the flow position, the plunger and the cavity of the housing has corresponding tapering cross-sections. In accordance with such an arrangement, the housing is formed with a removable bottom cap for insertion of the plunger during assembly thereof. The cap may be fixedly or removably attached to the housing.
In order to ensure that the plunger does not rotate within the housing, so as to obtain alignment of the communication conduit with the inlet and outlet ports, the plunger is formed, at least at the lower part thereof, with a portion having a non-circular cross-section received within a portion of the cavity, having a corresponding cross-section.
In order to increase sealing of the valve, at least in its flow-position, a sealing arrangement.is provided between the plunger and the walls of the cavity, at least at a location above the communication conduit, when the plunger is in the flow position. In accordance with such an arrangement, the plunger and the walls of the cavity are integrally formed with sealing rings and sealing grooves, respectively, engaging one another in the flow position.
By one embodiment of the invention, the flow path is a recessed well, formed at the top face of the plunger, and having an open wall portion at a side facing the outlet port, whereby at the sampling injecting position, the open wall portion is in flow communication with the outlet port of the housing.
In accordance with another embodiment of the invention, the flow path comprises one or more spacers, ensuring a clearance between a fore end of the luer connector of a syringe and the top face of the plunger, the arrangement being such that at the sampling-injecting position, said top face is in flow communication with the outlet port.
An important character of the valve in accordance with the present invention is lack of so-called dead-space, i.e. a volume in which blood or injected liquid may accumulate between sampling or injecting procedures, which may be either hazardous for a patient, or lead to false indications in case of blood sampling.